1. Field of the Invention
The present invention relates to a gate signal line driving circuit and a display device using the same.
2. Description of the Related Art
In known display devices, such as liquid crystal display devices, a method is often adopted in which a gate signal line driving circuit including plural shift register basic circuits, which output to plural gate signal lines gate signals that have a high voltage in order, is formed on the same substrate as a thin film transistor (hereinafter, referred to as a TFT) disposed in a display unit, example. A gate signal line driving circuit in the related art is disclosed in JP 2010-113247A.
For example, in a shift register basic circuit disclosed in JP 2010-113247A, an OFF voltage is applied to a switch of a gate line high voltage application circuit (transistors 93 and 94), which is turned on in a high signal period to apply a high voltage to a gate signal line, after the high signal period by an internal signal of a shift register basic circuit located at the subsequent stage. Accordingly, the gate line high voltage application circuit is turned off.
In addition, the shift register basic circuit provided in the gate signal line driving circuit may further include a gate line low voltage application circuit which is turned on in a low signal period (a period other than the high signal period) to apply a low voltage to the gate signal line so that the low voltage is stably output to the gate signal line during the low signal period. In this case, it is necessary to control a switch of the gate line low voltage application circuit similarly.
In order to do so, a control circuit which controls voltages applied to the switch of the gate line high voltage application circuit and the switch of the gate line low voltage application circuit, respectively, is required, and it is necessary to acquire a control signal for controlling the control circuit from the outside of the shift register basic circuit. This increases the circuit size of the shift register basic circuit.